code: def test_invalid_labels_2():
      y2 = np.where(y1 == 0, -1, 1)
      ada = Adaline(epochs=15, eta=0.01, random_seed=1)
      assert_raises(
          AttributeError,
          "y array must not contain negative labels.\nFound [-1  1]",
          ada.fit,
          X,
          y2,
          {(-1, 1)},
      )
  
file_path: mlxtend/mlxtend/classifier/tests/test_adaline.py
imports: import sys
  import numpy
  from sklearn.base import clone
  from mlxtend.classifier import Adaline
  from mlxtend.data import iris_data
  from mlxtend.utils import assert_raises
label_desc: Use image node_id 2 for calling a global function with example usage: test_invalid_labels_2() without return types